Vacuum switch



I April 1935. H. F. ANDERSON 1,997,288

VACUUM SWITCH Filed June 2, 1934 J l- INVENTOR j? 1M1 57 guwam" FZAnderson I 1 l 1. i

53 31 fiwy ATTOfiEY Patented Apr. 9, 1935 UNITED STATES PATENT OFFICE 7 Claims.

to electric vacuum particularly to a vacuum used in conjunction with This invention relates switches, and more switch adapted to be the ignition system of an internal combustion engine.

One object of this invention is to provide a vacuum switch of the above nature which will be particularly adapted to operate as an interrupter in the ignition system of a multi-cylinder internal combustion engine.

A further object is to provide an interrupter switch of the above nature in which the contact points are completely sealed within a vacuum chamber, and in which one of said points is mechanically operated from the-exterior of said chamber, thereby reducing arcing and consequent oxidation and pitting of the points, and eliminating the danger of explosions or fires which were foremerly caused when open contact points were used.

A further object is to provide a switch of the above nature in which the breaking distance between the points is reduced, thus enabling the switch to operate faster and with a smaller -electrical lag.

A further object is to provide a vacuum switch of the above nature which will be simple in construction, easy to install and manipulate, compact, and very eflicient and durable in use.

With these and other objects in view there have been illustrated on the accompanying drawing two forms in which the invention may be conveniently embodied in practice.

. In the drawing:

Fig. 1 represents a horizontal sectional view through the electric vacuum switch as it appears when installed upon a distributor base.

Fig. 2 is a plan view of the same on a reduced scale, and showing a condenser connectedthereto.

Fig. 3 .is a diagrammatic view of the ignition system of an internal combustion engine with the vacuum switch shown included in the circuit thereof.

Fig. 4 is a horizontal sectional view taken through a modified form of vacuuum switch.

Referring now to the drawing in which like reference numerals denote corresponding parts throughout the several views, the numeral l0 indicates a cup-shaped container for inclosing the vacuum switch, said container being preferably made cylindrical in shape and of suitable impervious metal, such as phosphor bronze. The open end of the container in is closed by a thin metallic resilient diaphragm ll having a central aperture from which extends a drifted neck I 2 for flexibly supporting an interrupter lever l3, which is tightly sealed in said neck as by solder. The outer edge of the diaphragm II is provided with an upstanding flange I4 which fits over the end of the container I0 and is hermetically tightly sealed thereto, as by the use of solder.

In order to support the container ID upon a horizontal metallic plate 16, forming part of a distributor head I l, provision is made of a lateral bracket member I 5, preferably soldered to said container and attached to said plate I6 by screws H! (see Fig. 3).

The outer end of the lever I3 is formed with an offset boss ISa having a tapped hole extending therethrough for receiving an adjustable screw l9 having a cam-engaging head 20, said screw I9 being adapted to be locked in adjusted position by a nut 2|. The screw head 20 is adapted to normally lie in contact with the periphery 22 of a multi-sided cam 23 which is rigidly mounted on the rotating timing shaft 24 of the distributor head H.

The inner end of the lever l3 carries a movable contact point 25 which is adapted to intermittently engage a stationary contact point 26 on the container ID for making and breaking the circuit of the ignition system. As shown in Fig. 1, the movable contact point 25 is detachably secured to the end of the lever l3 for convenience in assembly.

The stationary contact point 26 is integrally formed on the end of an elongated stud 21 mounted in a pair of insulating sleeve bushings 28 and 29 having cooperative engagement on opposite sides of a flattened surface 30 outwardly offset from the wall of the container l 0.

In assembling the stud 21 and bushings 28 and 29, a coating of shellac or similar insulating scab ing material may be spread between the contacting surfaces of said bushings and stud, and upon both sides of the offset metal surface 30, after which the parts may be tightly clamped together .by means of a nut 27a and washer 21b, thus effecting a very tight hermetic seal.

The exterior threaded end of the stationary contactor stud 21 is electrically connected by a wire 3| to a bindingpost 32 insulated by a non conducting bushing 16a from the distributor body plate I 6, said post 32 being joined as by aconductor 33 to the primary winding 31 of the induction coil 38.

The air is exhausted from the container l 0 to a high vacuum, preferably about 740 m. m. of mercury at 60 degrees F. However, it is also within the scope of the present invention to replace the air in the container with a gas which contains insuflicient conductive gas ions to maintain an are between the contactor points 25 and 26 when the circuit is opened. For permitting the air in the container to be thus exhausted or replaced, the container I0 is provided with a tubularpointed nub 34, which is adapted to be permanently sealed, as by fusing, when the proper vacuum has been produced.

Y In Fig. 3 the electric vacuum switch is shown in operating position in circuit with a conventional form of closed-circuit ignition system. The primary circuit which is indicated by a heavy line, leads from the positive terminal of a battery 35 through a switch 36, the primary winding Bl of the coil 38, through the contact points 25 and 26, the lever E3, the container ill, the body plate 16, which is grounded as indicated by the dotted line 39, the circuit being completed to the negative terminal of the battery 35 through the ground connection 39a.

A condenser 40 is connected at one end lla to the binding post 32 mounted on the distributor plate 16, the other end 20b of said condenser being connected to said plate I6 as by a bolt 400.

The secondary circuit is indicated by the light lines shown in Fig. 3, and comprises a winding M of fine wire connected to the ground by the wire t lb, the other end of said winding 4! being connected to the center terminal 42 of an insulating distributor head cap 53.. The terminal 02 makes contact with a metal springv Ml on an insulated rotating distributor brush 45 supported upon the upper end of the rotor shaft 24!.

As shown in Fig. 3, one end of the spring brush 414 when rotated passes close to, but does not touch, a plurality of metal distributor terminals 66 located in the head cap 43 (the number of terminals 46 depending on the number of engine cylinders). The terminals 46 are connected by wires 46a to the heads of the respective spark plugs 41 in the usual manner. The current after jumping the gaps from the brush 45 to the terminals 46 will flow through the wires 46a and jump across the gaps at the points of the spark plugs,

from which it will flow through the spark plug sockets 48 to the grounded engine block 49.

Operation Modified form In the modified form of the invention shown in Fig. 4, provision is made of an interrupter rod 50 which operates in the manner of a sliding plunger instead of as a rocking lever, as in the first form of the invention. The rod 50 is hermetically sealed to the neck l2 of the diaphragm II as before, and is provided at its outer end with a coaxial adjustable headed screw 5| adapted to be engaged by the rotary cam 23. The inner end of the sliding rod 50 is looped over to form a return bend 52, terminating in a movable contact teena e point 53 which is adapted to intermittently en- 57! secured to the open end of the cup-shaped container l0, said bracket being provided with a central bearing aperture for guiding said plunger rod 5e.

One advantage of the present invention is that by enclosing the interrupter switch in a vacuum, the usual separation of .020 between the contact points may be reduced to as low as .005" when breaking the circuit, without injurious sparking.

While there have been disclosed in this specification two forms in which the invention may be embodied, it is to be understood that these forms are shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosures but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, and for which it is desired to secure Letters Patent is:

1. In an electric switch, an evacuated metal container having a flat metal diaphragm on one face thereof, a stationary contact fixed to the inner wall of said container and insulated therefrom, a sealed lever fulcrumed in said diaphragm and carrying a movable contact on its inner end for engagement with said fixed contact, means for connecting said contacts outside of said container in circuit with a multiple ignition system, and means outside of said container for intermittently rocking said lever for continually opening and closing said switch.

2. In an electric switch, an evacuated metal container having a fiat metal diaphragm on one face thereof, a stationary contact fixed to the inner wall of said container and insulated therefrom, a sealed lever fulcrumed in said diaphragm and carrying a movable contact on its inner end for engagement with said fixed contact, means for connecting said contacts outside of said container in circuit with a multiple ignition system, and means for intermittently rocking said lever for continually opening and closing said switch.

3. In an electric switch, an evacuated metal container having a fiat metal flexible diaphragm on one face thereof, a stationary contact member passing through said container and insulated therefrom, a sealed movable contact rod passing through said diaphragm and electrically connected thereto, said rod carrying a movable contact on its inner end for engagement with said fixed contact, means for electrically connecting said stationary contact member and container in cir- 1 cuit with a multiple ignition system, and means for intermittently moving said rod for periodically opening and closing said switch.

4. In an electric switch, an evacuated metal cup-shaped cylindrical container, a thin metal wall of said container sealed thereto and insulated therefrom, a movable contact rod passing through the flanged aperture in said diaphragm and sealed thereto, said rod carrying a movable contact on its inner end for engagement with said fixed contact, means for electrically connecting said stationary contact member and container in circuit with a multiple ignition system, and means for intermittently moving said rod for periodically opening and closing said switch.

5. In an electric switch, an evacuated metal container having a fiat metal diaphragm on one face thereof, a stationary contact fixed to the iImer wall of said container and insulated there- 10 from, a sealed lever fulcrumed in said diaphragm and carrying a movable contact on its inner end for engagement with said fixed contact, means for connecting said contacts outside of said container in circuit with a multiple igniconnection to said base, said container having a fiat diaphragm on one side and an interior stationary contact insulated therefrom and also having a hermetically sealed movable contact member electrically connected therewith and extending at right-angles through said diaphragm, cam means carried by said timing shaft for periodically moving the movable contact into and out of engagement with said stationary contact, and means for connecting said stationary contact to an inductance.

7. In an electric switch, an evacuated container having a thin fiat flexible diaphragm on one face thereof, a stationary contact fixed to the inner wall of said container, a movable rod passing through said diaphragm and hermetically sealed therein, said rod carrying a movable contact on its inner end for engagement with said fixed contact, and means for intermittently moving said rod for opening and closing said switch.

HOWARD F. ANDERSON. 

